Body Tilt Research Articles

Neuroanatomy of reduced distortion of body-centred spatial coding during body tilt in stroke patients

Awareness of the direction of the body’s (longitudinal) axis is fundamental for action and perception. The perceived body axis orientation is strongly biased during body tilt; however, the neural substrates underlying this phenomenon remain largely unknown. Here, we tackled this issue using a neuropsychological approach in patients with hemispheric stroke. Thirty-seven stroke patients and 20 age-matched healthy controls adjusted a visual line with the perceived body longitudinal axis when the body was upright or laterally tilted by 10 degrees. The bias of the perceived body axis caused by body tilt, termed tilt-dependent error (TDE), was compared between the groups. The TDE was significantly smaller (i.e., less affected performance by body tilt) in the stroke group (15.9 ± 15.9°) than in the control group (25.7 ± 17.1°). Lesion subtraction analysis and Bayesian lesion-symptom inference revealed that the abnormally reduced TDEs were associated with lesions in the right occipitotemporal cortex, such as the superior and middle temporal gyri. Our findings contribute to a better understanding of the neuroanatomy of body-centred spatial coding during whole-body tilt.

Model Validation of Rigid Body Tilting of Deformed Spinning Discs with Spline-Guided Constraints

Model Validation of Rigid Body Tilting of Deformed Spinning Discs with Spline-Guided Constraints

Dynamic changes of the direction and angle of radiographic ocular lateral deviation in patients with lateropulsion after stroke onset.

To examine if radiographic ocular lateral deviation (rOLD) could be provoked in stroke patients with mild-to-moderate lateropulsion according to vertical perception. In this single-center, retrospective study, acute stroke patients with mild-to-moderate lateropulsion assessed by the Scale for Contraversive Pushing were enrolled. Computed tomography or magnetic resonance imaging was performed on all patients on admission and then according to their conditions. The direction and angle of rOLD were compared among three groups according to the responsible lesion: lateral medullary (LM), pontine (P), and hemispheric (H). Sixty-six patients (male, 47; average age, 67years) were enrolled and divided into the LM (n = 37), P (n = 8), and H (n = 21) groups. All patients had body tilt. Patients in the LM group showed body tilt to the ipsilesional side during hospitalization, while those in the P and H groups tilted to the contralesional side. All patients had rOLD at the final assessment at an average of 13days after onset; patients in the P and H groups showed contralateral rOLD, while those in the LM group showed ipsilateral rOLD if they did not have cerebellar or pontine lesions. Significant decreases in the angle and changes in direction of rOLD according to lesion site were observed during hospitalization. Serial changes in rOLD findings after stroke onset are different according to the responsible lesion. The direction of rOLD in most patients is in accordance with vertical perception after the acute stage of stroke.

Peliatan Style in Legong Keraton Lasem Performance

The Legong Keraton Lasem dance is one of the classical Balinese dances featuring Panji's story about the love story of King Lasem and Diah Rangke Sari. This classical dance first appeared and developed in the palace environment of Bali. There have been many research results on the Legong Keraton Dance. However, there has not been any research that reveals the Legong Keraton Lasem and Peliatan Style. The problems are: 1) How did the Peliatan Style in Legong Lasem Performance Originate?; 2) What is the form of the Peliatan Style in Legong Keraton Lasem dance?. The purpose of this research was to reveal the existence of the Peliatan Style in Legong Keraton Lasem Performance, which has catapulted Bali's name into the eyes of the world. This research was conducted using qualitative methods. The source of the data for this study was the Legong performance, the dancers, musicians, artists, cultural observers, and related communities who were selected based on purposive sampling and snowball techniques. All data that has been collected through observation, interviews, and literature studies will be analysed using aesthetic theory, hierarchical theory, and practical theory. The results showed that the Peliatan Style in Legong Keraton has a distinctive characteristic in the volume of dance movements performed, which tends to be large with the maximum tilt of the dancer's body. It is different from how to dance the Legong Keraton in general. The Legong Keraton Lasem with Peliatan Style emerged due to two factors, namely internal and external factors. Internal factors include the talent possessed by the Legong dancers themselves. They dance with the aim of satisfying their material and spiritual needs. Meanwhile, encouragement from outside came from the environment of Peliatan Village, which is indeed famous for its artistic activities; its people are very passionate about art every day.

Static cervico-ocular reflex in healthy humans

Background Dynamic cervico- (COR) and vestibulo-ocular reflex (VOR) contribute to stabilise visual images in the retina. The gain in dynamic COR is small in healthy individuals but increases in patients with vestibular dysfunction. Conversely, static COR has not been directly observed in healthy individuals. Objectives To elucidate the presence of static COR and quantify it in normal individuals in the roll plane. Methods Eleven healthy participants were included in the study. Eye torsions were measured using video oculography to evaluate the static COR induced by lateral neck flexion during a head-upright-with-body-tilt position at 15°, 30°, and 45°. The ocular counterroll (OCR) was compared during whole-body and head tilts to assess the influence of static COR on OCR. Results Static COR was significantly observed as eye torsion in the direction opposite to the body tilt. The head tilt OCR was significantly smaller than the whole-body tilt OCR to the right side but not to the left side. Conclusion Static COR exists in healthy individuals and tends to show higher amplitude as neck flexion stimulation increases.

Association Between Body Tilt and Egocentric Estimates Near Upright.

The mechanisms underlying geocentric (orientations of an object or the body relative to 'gravity') and egocentric estimates (object orientation relative to the 'body') have each been examined; however, little is known regarding the association between these estimates, especially when the body is nearly upright. To address this, we conducted two psychophysical experiments. In Experiment 1, participants estimated the direction of a visual line (subjective visual vertical; SVV) and their own body relative to gravity (subjective body tilt; SBT) and the direction of a visual line relative to the body longitudinal axis (subjective visual body axis; SVBA) during a small-range whole-body roll tilt. We evaluated the correlations between performance on each of these tasks as covariates of actual body tilt angles. Our results showed a significant correlation of performance (estimation errors) on the SVBA task with performance on the SBT task but not performance on the SVV task at the group level after adjusting for the actual body tilt angles, suggesting a link between the estimates for SVBA and SBT tasks. To confirm this relationship, in Experiment 2, we further assessed whether manipulating the subjective direction of the body axis by providing visual feedback in the SVBA task subsequently affected SBT performance. We found that feedback in the SVBA task significantly shifted the SBT angles even when the actual body angles were identical. The observed association between SVBA and SBT performance supports at least a partially shared mechanism underlying body tilt and egocentric estimates when the body is nearly upright.

Use of the posturography platform as a tool for quantitative assessment of imbalance and postural control in post-stroke patients in chronic phase

Background. Imbalance during standing, which is usually observed as an asymmetry in the weight shifting toward to the unaffected side of the body, is one of the most common factors affecting the independence and quality of life of post-stroke patients. Clinical assessment of imbalance in post-stroke patients is often conducted by visual observation using standardised tools (balance tests). However, quantitative analysis, using a posturographic platform, is more accurate and provides more information about the patient's functional status. The TYMO® device, used in this study, is a portable posturography platform that measures tilts of the body's center of mass and reports the results of the rehabilitation process. It enables an objective, direct and quantitative assessment of the patient's functional status. Such an assessment can contribute to significant effectiveness of physiotherapy and consequently improve the patient's quality of life and shorten the period of abstinence from work. Objective. Quantitative assessment of imbalance and postural control using a posturography platform (TYMO®) in patients after ischaemic stroke, in the chronic phase, as an important component of the functional diagnosis process and rehabilitation programme design. To emphasise the role of the posturography platform (TYMO®) as a tool for measuring static balance - symmetry of body weight distribution, and a tool for monitoring and reporting the results of physiotherapy treatment. Methods. In the current study, before and after two weeks of rehabilitation, quantitative measurements of balance on the TYMO® platform were made in a group of subjects (n = 60: adults, after ischemic stroke – first stroke episode, in chronic phase – up to 5 years after the stroke incident occurred) undergoing therapy using neurophysiological methods (PNF – Proprioceptive Neuromuscular Facilitation and NDT-Bobath – Neurodevelopmental Treatment according to the Bobath concept) and the SPIDER system (Strengthening Program for Intensive Developmental Exercises and activities for Reaching health capability). Measurements included: the distance marked by the patient's center of mass while performing the test, the medial-lateral and anterior-posterior tilts of the subject's body, the area of movement marked by the body's center of mass, the average speed at which the patient performed the movement to maintain the required position, and the distribution of the subject's weight. Based on the posturographic results obtained before therapy, it was possible to design a targeted rehabilitation programme. The magnitude of the difference in measurements before and after rehabilitation made it possible to assess the impact of the therapy on the patient's balance. In addition, it was a specific indicator of the accuracy of the selection of physiotherapeutic treatment (a large difference in the mean results before and after therapy reflected an improvement in the parameters of postural control, hence the effectiveness of the therapy) and determined the direction of the future rehabilitation programme. Results and conclusions. The parameters measured by the TYMO® platform are crucial in assessing the functional status of post-stroke patients, especially with regard to postural control or balance disorders. The results described confirm the validity of using quantitative assessment, using the posturography platform, as an important component of the functional diagnostic process and designing an rehabilitation programme. The TYMO® platform itself is a useful tool for measuring, monitoring and reporting the effects of physiotherapeutic treatment in post-stroke patients.

Three-Dimensional Human Pose Estimation from Sparse IMUs through Temporal Encoder and Regression Decoder

Three-dimensional (3D) pose estimation has been widely used in many three-dimensional human motion analysis applications, where inertia-based path estimation is gradually being adopted. Systems based on commercial inertial measurement units (IMUs) usually rely on dense and complex wearable sensors and time-consuming calibration, causing intrusions to the subject and hindering free body movement. The sparse IMUs-based method has drawn research attention recently. Existing sparse IMUs-based three-dimensional pose estimation methods use neural networks to obtain human poses from temporal feature information. However, these methods still suffer from issues, such as body shaking, body tilt, and movement ambiguity. This paper presents an approach to improve three-dimensional human pose estimation by fusing temporal and spatial features. Based on a multistage encoder-decoder network, a temporal convolutional encoder and human kinematics regression decoder were designed. The final three-dimensional pose was predicted from the temporal feature information and human kinematic feature information. Extensive experiments were conducted on two benchmark datasets for three-dimensional human pose estimation. Compared to state-of-the-art methods, the mean per joint position error was decreased by 13.6% and 19.4% on the total capture and DIP-IMU datasets, respectively. The quantitative comparison demonstrates that the proposed temporal information and human kinematic topology can improve pose accuracy.

Dependence of P/E tRNA hybrid formation on subunit rotation in the ribosome.

The ribosome, a massive nucleoprotein assembly that executes protein synthesis in all living cells, undergoes several large-scale functional rearrangements during the protein elongation cycle. Here we explore two such rearrangements in the ribosome bound tRNA molecules during the translocation step in bacteria, namely, P/E tRNA hybrid formation and inter-subunit rotation in the ribosome. We utilize multi-basin all-atom structure-based models and Ribosome Angle Decomposition (RAD) method to study the dependence of P/E hybrid formation on rotation of small subunit body with respect to the large subunit. Structure-based models provide simplified energetics with experimental atomic structures defined to be the potential energy minima. We employ these models to simulate spontaneous transition of the P-tRNA from P to E tRNA binding site on the large subunit for different degrees of small subunit body rotation. RAD method provides a complete coordinate system that describes any orientation of the ribosomal small subunit body and head in terms of rotation, tilt, tilt direction and translation. We identify reference E. coli structures at different degrees of body rotation but with minimal body tilt, head rotation and head tilt from the Ribosome Analysis Database based on RAD. Utilizing these methods, we explore the influence of subunit rotation on the free-energy barrier associated with P/E tRNA hybrid formation and obtain the quantitative dependence of P/E hybrid formation on subunit rotation.

Development and Testing of a Friction-Driven Forestry Electric Monorail Car

A friction-driven forestry electric monorail car based on a wheel hub motor is designed with the aim of solving the problems of the low transportation capacity, low running speed, large turning radius, and poor stability of low-slope mountain forestry monorails. The relationships between the minimum turning radius and the steering spring elasticity coefficient, between the body tilt and the anti-tip spring elasticity coefficient, and between the minimum turning radius of the monorail car and the distance between the two chassis and the two steering wheels was provided by the theoretical calculation and analysis of the key parameters of a dual-chassis structure, steering device, and anti-tip device. The dimensional parameters of the key components were determined. The three-dimensional design of the overall car was carried out, and the feasibility of the design was verified in kinematic simulation experiments. A performance test of the monorail car was conducted with the minimum turning radius, maximum load capacity, maximum full load speed, climbing degree, and center of gravity offset as indicators. The test results show that the monorail car has a minimum turning radius of 3.3 m, a maximum load capacity of 300 kg, a maximum speed of 20 km·h−1 fully loaded, a maximum gradient of 21°, and a unilateral vibration amplitude of 8 mm or less. The double-chassis structure and anti-tip device met the design requirements. The good transportation performance of the designed monorail car effectively solves the problems of a large turning radius and unstable driving of current forestry monorails. Additionally, the designed monorail car is environmentally friendly and efficient, meeting the requirements of monorail transporters for low-slope mountain forests and laying the foundation for the intelligent harvesting and transportation of mountain forest fruits.

Tilt in Place Microscopy: a Simple, Low-Cost Solution to Image Neural Responses to Body Rotations.

Animals use information about gravity and other destabilizing forces to balance and navigate through their environment. Measuring how brains respond to these forces requires considerable technical knowledge and/or financial resources. We present a simple alternative-Tilt In Place Microscopy (TIPM), a low-cost and noninvasive way to measure neural activity following rapid changes in body orientation. Here, we used TIPM to study vestibulospinal neurons in larval zebrafish during and immediately after roll tilts. Vestibulospinal neurons responded with reliable increases in activity that varied as a function of ipsilateral tilt amplitude. TIPM differentiated tonic (i.e., sustained tilt) from phasic responses, revealing coarse topography of stimulus sensitivity in the lateral vestibular nucleus. Neuronal variability across repeated sessions was minor relative to trial-to-trial variability, allowing us to use TIPM for longitudinal studies of the same neurons across two developmental time points. There, we observed global increases in response strength and systematic changes in the neural representation of stimulus direction. Our data extend classical characterization of the body tilt representation by vestibulospinal neurons and establish the utility of TIPM to study the neural basis of balance, especially in developing animals.SIGNIFICANCE STATEMENT Vestibular sensation influences everything from navigation to interoception. Here, we detail a straightforward, validated, and nearly universal approach to image how the nervous system senses and responds to body tilts. We use our new method to replicate and expand on past findings of tilt sensing by a conserved population of spinal-projecting vestibular neurons. The simplicity and broad compatibility of our approach will democratize the study of the response of the brain to destabilization, particularly across development.

Assessment of the relationship between the severity of the labor process and complications of pregnancy in female workers, the health of the fetus and newborn

In modern economic conditions, most women continue to work during pregnancy. According to the year of 2021 statistics, there is about half a million female workers are engaged in heavy physical work in Russia, which makes it relevant to study the impact of working conditions on the course of pregnancy, the health of newborns. The study aims to analyze and assess the occupational risk of health disorders of pregnant women workers, the health of their children born under the influence of a harmful production factor - the severity of labor. The researchers applied the method of analytical review and analysis of the data obtained to assess the risk of the impact of the severity of work on the health status, pregnancy of female workers and the condition of the fetus and newborn. Heavy physical labor, including lifting and moving heavy weights and intense physical exertion is especially unfavorable for pregnant workers. With a single lifting of loads weighing 11 kg or more, the risk of spontaneous miscarriage significantly increases by 31% (OR=1.31; 95% CI 1.08-1.58); preeclampsia - by 35% (OR=1.35; 95% CI 1.07-1.71). When lifting and moving loads with a total weight of 100 kg or more per shift, the risk of preeclampsia increases by 65% (OR=1.65; 95% CI 1.31-2.09), premature birth by 31% (OR=1.31; 95% CI 1.11-1.56); the risk of low birth weight infants increases by 108% (OR=2.08, 95% CI, 1.06-4.11). With intense physical activity during the shift, the risk of developing fetal sizes small for gestational age (SGA) increases by 34% (OR=1.34; 95% CI 1.03-1.73). When working "standing up" for four or more hours, the risk of premature birth increases by 11% (OR=1.11; 95% CI 1.02-1.22); SGA births - by 17% (OR=1.17; 95% CI 1.01-1.35). When working with a body tilt for an hour or more, the risk of developing preeclampsia in a pregnant worker increases by 51% (OR=1.51; 95% CI 1.09-2.08). Prolonged walking during a work shift increases the risk of developing SGA by 21% (OR=1.21; 95% CI 1.06-1.39). Working conditions characterized as heavy physical exertion statistically significantly increase the risks of spontaneous miscarriage, preeclampsia, premature birth, the development of a fetus small for gestational age, low newborn weight, etc. It is necessary to develop regulatory and methodological documents for the prevention of pregnancy complications in female workers engaged in physical labor.

Tilted 3D visual scenes influence lateropulsion: A single case study of pusher syndrome

ABSTRACT Introduction Hemiparetic stroke patients with so-called “pusher syndrome” (synonyms: contraversive lateropulsion, contraversive pushing) use their non-paretic extremities to push toward their paralyzed side and actively resist external posture correction. The disorder is associated with a distorted perception of postural vertical combined with a maintained, or little deviating perception of visual upright. With the aim of reducing this mismatch, and thus reducing contraversive lateropulsion, we manipulated the orientation of visual input in a virtual reality setup. Method We presented healthy subjects and an acute stroke patient with severe pusher syndrome a 3D visual scene that was either upright or tilted in roll plane by 20°. By moving the sitting participants in roll plane to the left and right, we assessed the occurrence of contraversive lateropulsion, namely the active resistance to external posture manipulation. Results With the 3D visual scene oriented upright, the patient with pusher syndrome showed the typical active resistance against tilts toward the ipsilesional side. He used his non-paretic arm to block the examiner’s attempt to move the body axis toward that side. With the visual scene tilted to the ipsiversive left, his pathological resistance was significantly reduced. Statistically, the tolerated body tilt angles no longer differed from those of healthy subjects. Conclusions We conclude that even short presentations of tilted 3D visual input can reduce symptoms of severe contraversive lateropulsion. The technique provides potential for a new treatment method of pusher syndrome and offers a simple, straightforward approach that can be effortlessly integrated in clinical practice. Trial Registration German Clinical Trials Register (DRKS00026700).

Suggested earthquake insurance claim evaluation criteria for building damage caused by soil liquefaction in Taiwan

Taiwan is located in a seismically active zone between the Eurasian Plate and the Philippine Sea Plate. Taiwan has a great geological diversity, but widespread alluvium deposits create the potential for soil liquefaction, which has considerable impact on society and the economy. Taiwan residential earthquake insurance was established after the Chi-Chi earthquake occurred in 1999, which had a death toll of more than 2400 and a ranking as the 12th costliest earthquake worldwide, with US$10 billion in property losses. The damage and impact of soil liquefaction were observed at the first time after the Chi-Chi earthquake. Nevertheless, the earthquake insurance claim criteria were based on the evaluation of structural components. Such criteria created difficulties for earthquake insurance inspectors in assessing the building damage caused by soil liquefaction during the 0206 Meinong earthquake in 2016 because such damage is often appeared as building rigid body tilt and settlement. As a result, geotechnical-related structural damage assessments were all performed by registered professional engineers. This study aims to develop and suggest earthquake insurance claim criteria for soil liquefaction-induced building damage, with the dual indices of settlement and tilt. The suggested criteria meet the requirements of current evaluation standards, reduce the necessity for further assessments performed by registered professional engineers, and would expedite the process of earthquake insurance claims for the ultimate goal of emergency relief.

The T4-L1-Hip Axis

This is a cross-sectional cohort. The aim was to describe sagittal plane alignment and balance in a multinational cohort of nondegenerated, asymptomatic adults. Current sagittal alignment targets were developed using correlations between radiographic and quality-of-life measures in spinal deformity patients, rather than disease-free samples leading to relatively poor accounting for variance within a population. Sagittal balance was defined using vertebral body tilt and spinopelvic alignment was defined as the vertebral pelvic angles from C2 to L5 (vertebral pelvic angle=vertebral tilt+pelvic tilt). Associations with pelvic incidence (PI) were assessed using linear regression. Multivariable linear regression was used to estimate a normal L1-S1 lordosis, adjusting for PI and the L1 pelvic angle (L1PA). Correlation between the L1 and T4 pelvic angles was assessed to define a normal thoracic alignment conditioned on lumbar alignment. Among 320 volunteers from 4 continents, median age was 37% and 60% were female. C2 tilt was independent of PI with minimal variation. PI was inadequate for estimating a normal lumbar lordosis (L1-S1, r2 =0.3), but was strongly associated with the lumbar pelvic angles (L1PA, r2 =0.58). Defining lumbar lordosis as a function of PI and L1PA resulted in high explained variance ( R2 =0.74) and the T4 pelvic angle had near perfect correlation with the L1PA ( r =0.9). We defined normal sagittal balance and spinopelvic alignment in a disease-free international volunteer cohort. Four parameters are either fixed or directly modifiable in surgery and can define a normal thoracic and lumbar alignment: the L1-S1 lordosis defined as a function of PI and the L1PA; and the T4 pelvic angle is nearly equivalent to the L1PA, aligning the T4-L1-hip axis.

Application of Gesture Estimation Method Based on Computer

This paper will study the computer vision pose estimation algorithm and apply it to fall detection. At present, the problem of aging cannot be ignored. There are more and more elderly people living alone. Due to their poor physical fitness, they are very easy to fall in daily life and bring great harm to the body and mind of the elderly. Therefore, they are in great need of means to monitor the daily life of the elderly in real time and make judgments on fall events. Driven by the rapid development of computer vision technology, human pose estimation has been widely used in fields such as motion recognition, motion posture scoring, and assisted rehabilitation therapy. The core of pose estimation is to detect the joint information and bone information of the human body from the image, and connect them to form a bone image to help the computer understand the human body information. The use of pose estimation for fall detection requires the extraction of human joint point information and bone information. In order to extract human joint point coordinates and bone images from video sequences, this paper has done a lot of research on computer vision pose estimation. First, the background subtraction method is studied. After that, the openpose pose estimation algorithm is studied. then studied the attitude estimation of Azure Kinect DK depth camera, focusing on its TOF principle and body tracking principle. After comparison, it is found that traditional pose estimation such as openpose is based on optical RGB images. In this paper, we mainly use Azure Kinect DK depth camera for fall detection. In the fall detection method, this paper uses the threshold method combined with pattern recognition method to detect falls. The thresholding method uses the head fall speed and the body tilt angle. The tilt angle of the upper body is used to solve the bending and squatting errors. The pattern recognition method transforms fall detection into two classification problems, fall and no-fall, and uses a support vector machine binary classification method combined with a directed gradient histogram to extract features from skeletal images for classification. The final experimental data show that this paper implements fall detection based on human posture estimation using Azure Kinect DK depth camera with high accuracy and practicality.

Effects of Various Body Positions on Arterial Stiffness as Assessed by Pulse Wave Velocity

BackgroundStandard measurements of arterial stiffness via pulse wave velocity (PWV) are conducted with participants in the supine position. When participants cannot tolerate supine position for prolonged procedure time (e.g., low back pain), accommodations may be made to tilt the bed up or bend the knees (i.e., Fowler’s positions). Moreover, a new testing device (Vicorder) that uses neck oscillometric cuff requires upper body tilt to avoid jugular vein interference on the recorded carotid pulse. Accordingly, this study aimed to investigate the effect of varying body positions on arterial stiffness measured via PWV.METHODSA total of 70 adults (43 women) varying widely in age (19‐66 years old), race/ethnicity (41% non‐white), and medical conditions were studied. Both carotid‐femoral PWV (cfPWV) and brachial‐ankle PWV (baPWV) were measured using two different testing devices (Omron vp1000plus and Vicorder) with participants in the reference supine (0º) position, 10º, 20º, 30º, and 40º upper body tilted‐up positions with and without knee flexion. The presence of jugular vein interference was documented visually on the oscillometric arterial waveforms at each body angle.RESULTSBoth cfPWV and baPWV measured at 10º upper body tilt‐up position were not significantly different from those assessed at the reference supine (0º) position. Upper body angle of 20º or greater produced PWVs that were significantly and gradually elevated (p<0.01). The magnitude of elevations in cfPWV were 7% (95% CI [6‐11%]) at 20º and 15% (95% CI [11‐18%]) at 40º while the elevations in baPWV were 8% (95% CI [6‐10%]) at 10º and 33% (95% CI [30‐36%]) at 40º compared with the supine (0º) position. Knee flexion did not alter cfPWV compared with straight knees whereas knee flexion decreased baPWV at the same upper body angle (p<0.05). Jugular vein interference in the Vicorder device appeared on 78% of participants in the supine (0º) position and gradually decreased as the upper body angle increased, resulting in 7% of the participants at 30º angle. The appearance of Jugular vein contamination was not affected by knee flexion.CONCLUSIONArterial stiffness as assessed by cfPWV and baPWV increased gradually and significantly by the use of semi‐Fowler position of ≥20º whereas bending knees at each angle decreased baPWV, but did not appear to influence cfPWV. Our present findings highlight the difficulty in comparing two different devices that are supposed to reflect the same arterial property.

Sensation of Anteroposterior and Lateral Body Tilt Induced by Electrical Stimulation of Ankle Tendons

While virtual reality technology enables users to walk on surfaces of various shapes in virtual environments, these experiences are often on a flat floor, and any discordance between visual and somatosensory information hampers the immersive experience. To resolve this issue, we have focused on the ankle joint angle as an essential cue in detecting the surface shape of the ground. To modulate the sensation of the ankle joint angle, we propose novel percutaneous electrical stimulation methods that stimulate four targeted ankle tendons: the tibialis anterior muscle tendon, the Achilles tendon, the peroneus longus muscle tendon, and the flexor digitorum longus tendon. Since electrically stimulating the elbow tendon is known to evoke reflexive hand movement, electrically stimulating the ankle tendon is expected to evoke a body tilt due to illusory changes in the ankle joint angle. In this study, we designed electrode configurations to stimulate the above four ankle tendons using a finite element analysis and investigated the effect of electrically stimulating the ankle tendons on the subjective sensation of body tilt and actual body sway through psychophysical experiments. The results revealed that applying this stimulation with our novel electrode configurations can induce a subjective sensation of body tilt and actual body sway in a direction opposite to the stimulated part.

Dynamic Locomotion Teleoperation of a Reduced Model of a Wheeled Humanoid Robot Using a Whole-Body Human-Machine Interface

Bilateral teleoperation provides humanoid robots with human planning intelligence while enabling the human to feel what the robot feels. It has the potential to make physically capable humanoid robots dynamically intelligent. However, dynamic bilateral locomotion teleoperation remains as a challenge due to the complex dynamics it involves. This work presents our initial step to tackle this challenge via the concept of wheeled humanoid robot locomotion teleoperation by body tilt. Specifically, we developed a whole-body human-machine interface (HMI) capable of applying force feedback to the human pilot. Then, we designed a force feedback law and two teleoperation mappings that map the human’s body tilt to the robot’s velocity or acceleration. We compared the two mappings and studied the force feedback’s effect via an experiment, where seven human subjects teleoperated a simulated robot with the HMI to perform dynamic target tracking tasks. The experimental results suggest that most subjects performed the tasks better with the velocity-based mapping, and that the force feedback improved their performances. Yet, the subjects exhibited two distinct teleoperation styles, which benefited from the force feedback differently. Moreover, the force feedback affected the subjects’ preferences on the teleoperation mappings.

Development of an Attitude Adjustment Crawler Chassis for Combine Harvester and Experiment of Adaptive Leveling System

Body tilt is typically unavoidable for agricultural vehicles or platforms when operated over tough terrain in agricultural production, and, therefore, it is not possible to guarantee the operation performance. Current leveling methods mainly focus on wheeled vehicles or adjustment for single working parts rather than the vehicle body, and few of them could be applied to crawler vehicles. The objective of this research was to put forward an adaptive leveling system for combine harvesters based on the development of a new four-point lifting adjustable crawler chassis. The working principle of the proposed adjustable mechanism was studied on the basis of the analysis of adjustment characteristics under multiple posture adjustment conditions in a RecurDyn environment. The design relies on the combination of the attitude detection of the leveling system and adjustment calculation of driving hydraulic cylinders according to the established mathematical models. Within the designed adjustable extent (including adjustment range of vehicle height 0–87.8 mm, lateral inclination ±3.98° and longitudinal inclination −2.9–5.2°), the leveling performance of lateral and longitudinal inclination was then tested separately. The experiment showed that the leveling system could achieve automatic leveling with an accuracy of ±0.4° and could provide technical support for the development of crawler vehicles.